Dose–response association between maternal body mass index and small for gestational age: a meta-analysis

Abstract

Objective: This study was performed to determine the dose–response relationships between maternal anthropometric variables and risk of small for gestational age (SGA).

Methods: Linear and nonlinear dose–response meta-analyses were performed to summarize the adjusted relative risks of SGA. Ten databases, including PubMed (MEDLINE), were searched. Study quality was assessed using the Newcastle–Ottawa scale.

Results: A total of 323 243 subjects were extracted from high-quality studies to evaluate maternal body mass index (BMI) (n = 9). The generalizability of the findings regarding height and weight (n = 3 and 2, respectively) was limited. The non-linear model (p for non-linearity < 0.05) showed a significant and inverse association of maternal BMI with risk of SGA, although only two of nine studies involved obese women (i.e. BMI ≥ 30 kg/m²). The slope of the dose–response curve between maternal BMI and SGA (i.e. the amount of reduction in SGA risk) decreased gradually.

Conclusions: SGA risk may be reduced by increasing BMI of normal (i.e. 18.5 kg/m²≤ BMI < 25 kg/m²) and overweight women (i.e. 25 kg/m²≤ BMI < 30 kg/m²), but the most marked reduction is achieved by increasing BMI of underweight women (i.e. BMI < 18.5 kg/m²).

• Anthropometry
• body mass index
• meta-analysis
• risk
• small for gestational age

Acknowledgements

The author is grateful to the staff of the Medical Library of the Japan Medical Association (Tokyo, Japan) for help in retrieving the full texts of the articles.

Declaration of interest

The author has no potential competing interests to disclose, and no external funding was provided for this manuscript. English language usage was checked by Dolphin Corporation (1005 Kichijyoji Nagatami City Plaza 1–20-1 Kichijyoji Honmachi. Musashino, 180–0004, Japan, [email protected]).

Supplementary material available online

Supplementary Figures 1 and 2, Tables 1 and 2.